package com.heima.kafka.sample;

import org.apache.kafka.clients.consumer.*;

import java.time.Duration;
import java.util.Collections;
import java.util.Properties;

/**
 * 消费者
 */
public class ConsumerQuickStart {
    public static void main(String[] args) {
        // 1.kafka的配置信息
        Properties prop = new Properties();
        prop.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.200.130:9092");
        prop.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        prop.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        prop.put(ConsumerConfig.GROUP_ID_CONFIG, "group2"); // 同组一个生产者只能向一个消费者投递消息；不同组一个生产者可以向多个消费者投递消息

        // 额外配置，禁止自动提交偏移量，避免消费者挂掉以后偏移量和实际消费的位置不一致的问题
        prop.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);

        // 2.创建消费者对象
        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(prop);
        // 3.订阅主题
        consumer.subscribe(Collections.singletonList("topic-first"));

        // 4.拉取消息
        // 同步、异步组合使用
        try {
            while (true) {  // 一直保持监听状态
                ConsumerRecords<String, String> consumerRecords = consumer.poll(Duration.ofMillis(1000));
                for (ConsumerRecord<String, String> consumerRecord : consumerRecords) {
                    System.out.println(consumerRecord.key());
                    System.out.println(consumerRecord.value());
                    System.out.println(consumerRecord.partition());

                    /*try {
                        // 同步提交偏移量
                        consumer.commitSync();
                    } catch (CommitFailedException e) {
                        System.out.println("提交失败的异常：" + e);
                    }*/
                }
                consumer.commitAsync();
    /*            // 异步提交偏移量
                consumer.commitAsync(new OffsetCommitCallback() {
                    @Override
                    public void onComplete(Map<TopicPartition, OffsetAndMetadata> map, Exception e) {
                        if (e != null) {
                            System.out.println("当前错误偏移量" + map + "提交失败的异常：" + e);
                        }
                    }
                });*/
            }
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("提交失败的异常：" + e);
        } finally {
            consumer.commitSync();
        }
    }
}
